Semiconductor device and control system using the same

Abstract

It is an object of the present invention to provide a technique capable of reducing power consumption of a semiconductor device even when the semiconductor device operates at high speed. The semiconductor device includes a module for outputting a signal, a delay element, a first output circuit having an input and an output, a first external terminal connected to the output of the first output circuit and to be connected to a signal wiring, and a second external terminal. The input of the first output circuit receives the signal delayed by the delay element. The second external terminal receives the signal without passing through the delay element. The signal of the second external terminal is used to change the potential level of the signal wiring to be connected to the first external terminal before the first output circuit changes the potential of the first external terminal based on the delayed signal.

What is claimed is: 
     
       1. A control system comprising
 a terminal controller for being input a first signal, and 
 a charge/discharge control transmission circuit being coupled with the terminal controller via a first cross point and being input a second signal, 
 wherein the first signal is made by delaying of the second signal, and 
 wherein the charge/discharge control transmission circuit controls a voltage of the first cross point based on the second signal when a signal level of the first signal differs from a signal level of the second signal, and 
 wherein the charge/discharge control transmission circuit moves the voltage of the first cross point close to a source voltage, when the signal level of the first signal is low level and the signal level of the second signal is high level. 
 
     
     
       2. A control system, comprising:
 a first semiconductor device; 
 a second semiconductor device; 
 a signal wiring provided between the first semiconductor device and the second semiconductor device; and 
 a charging and discharging device connected to the signal wiring, 
 wherein the first semiconductor device includes:
 a communication circuit for outputting a signal; 
 a delay circuit; 
 an output circuit having an input and an output; 
 a first external terminal connected to the output of the output circuit and connected to the signal wiring; and 
 a second external terminal, 
 
 wherein the input of the output circuit receives the signal delayed by the delay circuit, 
 wherein the second external terminal receives the signal without passing through the delay circuit, and 
 wherein the charging and discharging device receives the signal from the second external terminal to control a voltage level of the signal wiring, 
 wherein the first semiconductor device includes:
 an output delay control unit including the delay circuit; and 
 a charge/discharge control transmission circuit connected to the output delay control unit, 
 
 wherein the charge/discharge control transmission circuit controls whether or not the signal output from the communication circuit is delayed using the delay circuit, 
 wherein the charge/discharge control transmission circuit outputs a control signal for changing the voltage level of the signal wiring by the charging and discharging device to a predetermined voltage level between a first reference potential and a second reference potential lower than the first reference potential when the signal output from the communication circuit is delayed using the delay circuit, and 
 wherein the charge/discharge control transmission circuit does not output the control signal for changing the voltage level of the signal wiring by the charging and discharging device to the predetermined voltage level between the first reference potential and the second reference potential when the signal output from the communication circuit is not delayed using the delay circuit. 
 
     
     
       3. The control system according to  claim 2 , wherein the charging and discharging device changes the voltage level of the signal wiring to the predetermined voltage level between the first reference potential and the second reference potential before the output circuit changes the voltage level of the signal wiring to the first reference potential or the second reference potential lower than the first reference potential based on the delayed signal. 
     
     
       4. The control system according to  claim 2 ,
 wherein the charging and discharging device includes:
 a control circuit; and 
 a charging/discharging unit, and 
 
 wherein the control circuit detects a shortage of the charge amount of the charging/discharging unit and charges the charging/discharging unit. 
 
     
     
       5. A control system comprising:
 a first semiconductor device; 
 a second semiconductor device; 
 a plurality of signal wirings provided between the first semiconductor device and the second semiconductor device; and 
 a charge/discharge device connected to the plurality of signal wirings for controlling voltage levels of the plurality of signal wirings, 
 wherein the first semiconductor device includes:
 a plurality of communication circuits; 
 an output delay control unit including a delay circuit; 
 a charge/discharge control transmission circuit connected to the output delay control unit; and 
 a plurality of output circuits to which signals from the plurality of communication circuits are input via the output delay control unit and connected to the plurality of signal wirings, 
 
 wherein the charge/discharge control transmission circuit transmits terminal information to the charge/discharge device, 
 wherein the charge/discharge device controls voltage levels of the plurality of signal wirings based on the terminal information, 
 wherein the charge/discharge control transmission circuit controls whether or not the signals output from the plurality of communication circuits are delayed by using the delay circuit and supplied to the plurality of output circuits, and 
 wherein when the signal output from the plurality of communication circuits is delayed using the delay circuit, the charge/discharge control transmission circuit changes the voltage level of the plurality of signal wirings to a predetermined voltage level between a first reference potential and a second reference potential by the charge/discharge device before the plurality of output circuits change the voltage level of the plurality of signal wirings to the first reference potential or the second reference potential lower than the first reference potential based on the delayed signal. 
 
     
     
       6. The control system according to  claim 5 , wherein the charge/discharge control transmission circuit transmits the terminal information to the charge/discharge device using a clock synchronous protocol. 
     
     
       7. The control system according to  claim 5 , wherein the charge/discharge control transmission circuit transmits the terminal information to the charge/discharge device using a paced synchronous protocol. 
     
     
       8. The control system according to  claim 5 ,
 wherein the charge/discharge device includes a control circuit and a charging/discharging unit, and 
 wherein the control circuit detects a shortage of the charge amount of the charging/discharging unit and charges the charging/discharging unit.